1. Field of the Invention
The present invention relates to an integral-type heat exchanger comprising two-types of heat exchangers which are connected together or disposed adjacent to each other prior to mount on an automobile.
2. Description of the Related Art
So-called integral heat exchangers have been recently developed, wherein a condenser for cooling purposes is connected to the front face of a radiator. An example of the integral heat exchangers is disclosed in Japanese Patent Publication No. Hei. 1-224163.
FIG. 38 illustrates an integral-type heat exchanger as disclosed in Japanese Patent Publication No. Hei. 1-247990. This heat exchanger comprises a first heat exchanger 1 to be used as a radiator and a second heat exchanger 3 to be used as a cooling condenser, both of which are positioned in parallel with each other.
The first heat exchanger 1 comprises an aluminum upper tank 5 which is opposite to and spaced a given distance from a lower aluminum tank 7, and an aluminum tube 9 connecting together the upper and lower tanks 5 and 7. The second heat exchanger 3 comprises an upper aluminum tank 11 which is opposite to and spaced a given distance from a lower aluminum tank 13, and an aluminum tube 15 connecting together the upper and lower tanks 11 and 13.
As illustrated in FIG. 39, the aluminum tubes 9 and 15 of the first and second heat exchangers 1 and 3 are in contact with an aluminum fin 17 spreading across the aluminum tubes. The first and second heat exchangers 1 and 3 form a heat radiation section (a core) 19 by means of the common fin 17.
The first and second heat exchangers 1 and 3, and the heat dissipation section (the core) 19 are integrally bonded together by brazing.
In this conventional integral-type heat exchanger, all of the upper tanks 5, 11 and the lower tanks 7 and 13 of the first and second heat exchangers 1 and 3 are formed so as to have a circular cross section, thereby presenting the following problems.
Normally, the first heat exchanger 1 to be use as the radiator is larger than the second heat exchanger 3 to be used as the cooling condenser, and the reason is as follows. Generally, the amount of coolant flowing in the radiator is larger than that in the cooling condenser. Therefore, it should be necessary to decrease the resistance of the tank of the radiator to the coolant flowing therein as compared with the tank of the cooling condenser. Further, it should be necessary to increase the capacity of the tank of the radiator as compared with the tank of the cooling condenser. Accordingly, the radiator becomes larger than the cooling condenser.
Therefore, as illustrated in FIG. 40, the distance (or a tubing pitch La) between the tubes 9 and 15 becomes large because of the difference in diameter between the upper tanks 5 and 11, as well as between the lower tanks 7 and 13, thereby increasing the thickness Wa of the heat radiation section (core) 19. The area 16 between the tubes 9 and 15 becomes a dead space.
As illustrated in FIG. 41, with the purpose of reducing the thickness of the heat radiation section (core) 19, a tube hole 20 formed in the upper and lower tanks 5 and 7 of the first heat exchanger 1 could be moved so as to become closer to the second heat exchanger 3. However, such a modification requires a difficult boring operation, and hence this idea is not suitable in view of practicality.